光固化水凝胶—干细胞外泌体复合材料修复关节软骨损伤的研究

Currently, articular cartilage injury is a great challenge for clinical treatments. Hydrogel can provide cells with 3D microenvironment that is highly similar to natural extracellular matrix. Thus, it has been widely used as cell-scaffolds for articular cartilage regeneration in the past few years. However, it is usually hard for most of the current hydrogel materials to effectively integrate with cartilage matrix, which will avianize their reparative effects for cartilage injury. Recently, our group have developed a photoinduced imine crosslinking (PIC) hydrogel system, which showed superior operability, biocompatibility and most importantly tissue adhesive and integration ability，and it is quite suitable as scaffold material for articualr cartilage regeneration. In this project, we encapsulate induced pluripotent stem cell-derived exosomes which exhibit great ability to promote tissue repair and regeneration in the PIC hydrogel to develop an exosome-composited hydrogel. We will fully investigate its reparative ability though a series in vitro and in vivo experiments to optimize and build an exosome composited hydrogel scaffold with highly effective cartilage repair ability. The smooth implementation of this project would provide a novel approach for the treatment of articular cartilage injury.

关节软骨损伤的有效修复一直是困扰临床的世界性难题。近年来，水凝胶材料因其具有为软骨细胞提供模拟细胞外基质微环境的特性，在软骨损伤治疗研究领域中得到了广泛的关注。但是，水凝胶材料也存在难以与软骨基质进行有效粘附与整合的缺陷，影响着它们作为生物支架材料修复关节软骨损伤的性能。申请人在前期研究中成功构建了兼具优异操作性、生物相容性、组织粘附整合性于一体的光致亚胺交联水凝胶体系，为软骨损伤的修复提供了一种理想的生物支架材料。据此，本项目拟将具有强大组织修复功能的诱导多能干细胞来源的外泌体负载到光致亚胺交联水凝胶中，通过系列体内外实验对其软骨损伤修复功能进行充分评价与分析，优化构建一种可高效促进软骨再生与修复的复合水凝胶生物材料。该项目的顺利实施，将为软骨损伤的修复研究提供新的思路和手段。

关节软骨损伤修复与骨关节炎的有效干预一直是临床的挑战性难题。近年来，间充质干细胞（MSCs）分泌的外泌体促进软骨修复与抑制关节炎的作用得到了广泛的研究和证实。然而，关节腔的局部环境不利于纳米尺寸外泌体的长期驻留，严重影响外泌体治疗功能的发挥。本项目利用光致亚胺交联水凝胶作为多能干细胞诱导间充质干细胞（iPSC-MSC）分泌的外泌体的载体材料，构建了一种复合外泌体的关节软骨损伤修复材料。研究结果表明由光致亚胺交联基团NB修饰的透明质酸（HA-NB）和明胶（gelatin）制备光致亚胺交联水凝胶可以在20 s时间内成胶，最终存储模量为500 Pa (395 nm, 20 mW/cm2)。该凝胶的前体溶液可以和外泌体悬液均匀混合制备负载iPSC-MSC外泌体的复合软骨修复凝胶，该凝胶表现出了良好的细胞相容性与外泌体的驻留能力，且可以牢固的粘附在软骨组织表面，与软骨组织有效整合。兔子的全层关节软骨损伤模型证实，复合外泌体的光致亚胺交联水凝胶可以有效促进整合性透明软骨组织的再生，其作用效果显著优于单次外泌体注射的修复效果。为外泌体促进软骨组织修复提供了全新的应用方法，具有一定的应用潜力。